Institutional Stockholder Services recommended that Sprint Nextel Corp. stockholders vote in favor of a deal to sell control of the Overland Park-based company to SoftBank. The Japanese company proposes to buy a 70 percent stake in Sprint for $20.1 billion.

ISS gave its nod to SoftBank because it would alleviate Sprint’s debt burden and provide capital to improve the company’s network. It also cited SoftBank’s success in building up the Japanese wireless market.